Process and apparatus for building tyres

An apparatus for building a tyre, comprising:

• a building drum comprising two axially approachable halves and having an outer circumferential surface defining an application diameter;
• devices for applying at least one carcass ply having axially opposite end flaps around an outer circumferential surface of the building drum;
• devices for engaging an annular anchoring structure with a fitting diameter smaller than said application diameter coaxially around each of the end flaps of said at least one carcass ply, so as to make a carcass sleeve;
• devices for forming at least one pair of sidewalls around the carcass sleeve, by laying of at least one first continuous elongated element in the form of approached coils;
• at least one pair of auxiliary support members, each having at least one circumferential rest surface extending in a continuation of the outer circumferential surface of the building drum to support at least the axially opposite end flaps of said at least one carcass ply, being removably engaged with the building drum, and being in axially approached relationship with a respective half of the building drum,
• wherein each auxiliary support member is removably engaged with the building drum at least at a connecting member carried by the building drum, wherein each connecting member is in the form of a cylindrical sleeve;
• and
• at least one pair of auxiliary shaping members capable of being removably engaged with the building drum by a fastening device operatively carried by a flanged element of each auxiliary shaping member, each auxiliary shaping member being capable of being connected at least to a respective one of said connecting members in place of each auxiliary support member, the fastening device comprising a guide sleeve internally defining an engagement seat capable of slidably engaging on a cylindrical surface of the cylindrical sleeve of the respective one of said connecting members, each auxiliary shaping member having a continuous circumferential extension to hermetically seal the carcass sleeve at the annular anchoring structures thereby facilitating radial expansion of the sleeve itself through inflation during the shaping and maintenance of the inflated state following the shaping.